Growth Repressor GmRAV Binds to the GmGA3ox Promoter to Negatively Regulate Plant Height Development in Soybean.

Plant height is an important component of plant architecture, and significantly affects crop quality and yield. A soybean (Related to ) transcription factor containing both AP2 and B3 domains is a growth repressor. Three () transgenic lines displayed extremely shorter height and shortened internodes compared with control plants, whereas transgenic inhibition of expression resulted in increased plant height. soybean plants showed a low active gibberellin level and the dwarf phenotype could be rescued by treatment with exogenous GA treatment. ChIP (Chromatin immunoprecipitation)-qPCR assay showed that GmRAV could directly regulate the expression of the GA4 biosynthetic genes () by binding two CAACA motifs in the promoter. The promoter was bound by GmRAV, whose expression levels in leaves were both elevated in and decreased in soybean plants. Transient expression assay in also showed that the effector strongly repressed the expression of LUC reporter gene driven by promoter containing two CAACA motifs. Together, our results suggested that GmRAV protein repressed the expression of by directly binding to the two CAACA motifs in the promoter to limit soybean plant height.